If using the exposure suggestion from the cameras meter and exposing to the center (0, or the "correct" exposure), then using Av shouldn't make any difference from using manual...expect that in changing light conditions in Manual you will be constantly having to scroll the adjustment wheel. But on a controlled setting, I can see the Manual being a better option, because once you get the exposure you want, you can take multiple exposures with uniformity.

So basically....my over thinking beginner thought is that outside of a [somewhat] controlled setting and/or intentionally over/under exposing....Manual doesn't really make sense.

Feel free to correct me where I am wrong...I honestly would like to know how/if my logic is flawed on this. That said...I tend to shoot in M just cause I think it makes me learn more.

battletone you are right - when the camera meter is working and giving you the exposures you want - or simply needs a little correction (eg during daytime light I often find I like to underexpose a little to save highlights) then using aperture priority is far quicker than using manual mode and great for being on the go - walking and such.

Of course studio conditions, times when flash is the dominant light source and other examples, like at night, then full manual is often the way you need to go because what the camera gives you is not what you want. Take flash as the dominat light source - the camera meter looks at the current light in the scene, whilst hte flash is attached and on the camera can't meter for the flashlight as its not present until you take the shot( at which point its too late to change the settings) so one has to slip into manual mode if the flash light is dominant (ie its providing most of the lighting as oppposed to just filling in a few shadows).

ALWAYS use the mode that will get you the best shot possile in the situation your in - if for you that is auto mode then use it - if its manual then use that - if its aperture or shutter priority then use those.
The settings will still give the exact same result - f5.6, ISO 200, 1/320sec is the same in aperture priority mode or manual mode.

I'm probably in "A" 90% of the time or more, simply because I usually want to be in control of aperture more than anything, and don't mind as much where shutter falls to make that happen. Then I can dial in the light with EV steps if need be without taking the camera from my eye.

Next, "M", and that's mostly for studio shots with multiple off-camera strobes. I'm still interested in controlling aperture the most, but the camera meter won't compensate correctly for all the strobes in "A" so I take full control.

Finally, "T", on the rare occasions that I want to use motion to pan a subject or capture waterfalls or something like that.

I shoot on aperture priority 90% of the time too.....But I use exposure compensation like it's second nature.... That button will wear out first....lol.... I also use the ISO button a million times a shoot to control SS.